Concentrated photovoltaic technology – also known as CPV – generates electricity using optics (such as lenses or mirrors) to focus sunlight onto a small area of high efficiency solar cells. These systems can produce much more energy than typical PV panels, and also require less land.
Concentrated solar photovoltaic systems are most suitable for regions with intense sunlight, like deserts, and can be made up of many small dishes on a panel, or of a few large parabolic dishes.
Efficiency of CPV
Conventional PV panels use unconcentrated sunlight, whereas the solar cells used in CPV systems concentrate the sunlight up to 500 times. These multi-junction solar cells that have multiple layers of substrate to catch different wavelengths of light.
A close up of a SolFocus CPV panel. Credit: SolFocus
These are different from the silicon used in residential solar panels, and are able to convert about 40 percent of incoming sunlight into electricity.
Solar cells generate more electricity when exposed to more sunlight, but efficiency decreases as temperature rises. So to keep CPV systems working, they must be kept cool by using heat sinks.
Cost of CPV
While the high efficiency cells are more expensive, because of the concentrating effect, CPV systems require much less absorbent material than conventional PV panels. Rather than having large areas of PV material, CPV systems use cheaper materials (steel, mirrors) to concentrate the sunlight.
Concentrated photovoltaics do also have tracking systems, adding to the overall construction cost.
Proponents of CPV say that it costs less per installed watt than traditional PV panels, but again the most important factor is sunlight availability. Another benefit is that CPV can be cost-effective both at a utility scale but also at a smaller scale.
A Solar Systems CPV installation in Australia. Photo Credit: Solar Systems
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